ASYMMERTIC TURNING FILM WITH MULTIPLE LIGHT SOURCES

• US 20170175976A1
• Filed: 03/27/2015
• Published: 06/22/2017
• Est. Priority Date: 04/01/2014
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Benoit, Gilles J., Epstein, Kenneth A., Thompson, David Scott, Johnson, Nicholas A., Wheatley, John A., Lauters, Michael E.
• Granted Patent: US 10,371,350 B2
• Time in Patent Office: Days
• CPC Class Codes: F21V 5/002 using microoptical elements for redirecting or diffusing light
• CPC Class Codes: F21V 5/08 producing an asymmetric light distribution
• CPC Class Codes: F21V 9/14 for producing polarised light
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0047 for use with a light source G02B19/009, G02B19/0095 take precedence; details of lighting devices in general F21V; non-semiconductor lasers having optical devices external to the laser cavity H01S3/005
• CPC Class Codes: G02B 5/0231 the surface having microprismatic or micropyramidal shape macroscopic prism arrays G02B5/045
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

Optical systems are disclosed. More particularly, optical systems including an asymmetric turning film (110) with at least a first (120) and second light source (130) are disclosed. Selection of geometries for the asymmetric turning film can enable different output viewing angles depending on the selective illumination of the first light source, the second light source, or both. The optical systems disclosed may be suitable in both luminaires and displays.

Claims

1. An optical system, comprising:

a first light source and a second light source having differently oriented light distributions;

an asymmetric turning film comprising a first major surface and a second major surface, wherein the first major surface is substantially smooth and the second major surface comprises a plurality of microstructures each comprising a first face having a first shape and a second face having a different second shape; and

a polarizer;

wherein light from the first light source is preferentially reflected by the first face but not the second face;

wherein light from the second light source is preferentially reflected by the second face but not the first face; and

wherein the asymmetric turning film is laminated to the polarizer.

2. The optical system of claim 1, further comprising a lightguide configured to transport

light from at least one of the first light source and the second light source.

3. The optical system of claim 2, further comprising a second lightguide configured to

transport light from at least one of the first light source and the second light source.

4. The optical system of claim 3, wherein the first lightguide and the second lightguide are

stacked.

6. The optical system of claim 1, wherein the first shape is substantially flat and the second shape is substantially curved.

7. The optical system of claim 1, wherein each of the plurality of microstructures is the same lateral cross-sectional shape.

8. The optical system of claim 1, wherein each microstructure of the plurality of microstructures further comprises a third face having a third shape, wherein either light from the first light source is preferentially reflected by the first face and the third face but not the second face or light from the second light source is preferentially reflected by the second face and the third face but not the first face.

9. The optical system of claim 1, further comprising a second plurality of microstructures, each comprising a third face having a third shape and a fourth face having a different fourth shape, wherein the third face preferentially reflects light from the first light source but not the second light source, wherein the fourth face preferentially reflects light from the second light source but not the first light source, and wherein at least two of the first shape, the second shape, the third shape, and the fourth shape are different.

10. The optical system of claim 1, wherein the second major surface of the asymmetric turning film includes at least one of an antireflective coating or an antireflective structured surface.

12. The optical system of claim 1, wherein at least one of the first face or the second face includes a sawtooth or sinusoidal surface.

13. The optical system of claim 1, wherein the optical system has two display modes, wherein in the first mode, only the first light source emits light, and in the second mode, only the second light source emits light.

14. The optical system of claim 13, wherein the optical system has a third mode, wherein in the third mode, both the first light source and the second light source emits light.

16. A luminaire comprising the optical system of claim 1.

17. A display comprising the optical system of claim 1.

5. An optical system, comprising:

a first light source and a second light source having differently oriented light distributions;

a first lightguide configured to transport light from at least one of the first light source and the second light source;

a second lightguide configured to transport light from at least one of the first light source and the second light source; and

an asymmetric turning film comprising a first major surface and a second major surface, wherein the first major surface is substantially smooth and the second major surface comprises a plurality of microstructures each comprising a first face having a first shape and a second face having a different second shape;

wherein light from the first light source is preferentially reflected by the first face but not the second face;

wherein light from the second light source is preferentially reflected by the second face but not the first face; and

wherein the first lightguide and the second lightguide are stacked.

11. The optical system of claim 5, wherein the first major surface of the asymmetric turning film includes at least one of an antireflective coating or an antireflective structured surface.

15. An optical system including an asymmetric turning film having a display surface and two display modes, wherein in the first mode, the display surface emits light having a first characteristic set of viewing angles, and wherein in the second mode the display surface emits light having a second characteristic set of viewing angles, wherein the first characteristic set of viewing angles and the second characteristic set of viewing angles have different widths.